Tri-substituted glycols and method of making same



Patented Jan. 30, 1951 UNITED STATES OFFICE [FRI-SUBSTITUTED GLYCOLS ANDMETHOD OF MAKING SAME Ernst Bergmann,

London, England, assignor to folymerisable Products Limited, LondonCounty, England, a British company No Drawing. Application December 23,1946, Serial No. 718,109

2 Claims. (01. 260-635) Glycols are important as starting materials forplasticisers, as components of anti-freeze mixtures and either as suchor in form of derivatives as insecticides, and for other uses.

The present invention consists in a process for the production oftertiary-secondary glycols of the following general formula C-OH.R3R4511 $11 in which R R and R are 'monovalent hydrocarbon radicals, and Ris preferably methyl; R and R can be separate alkyl groups or with theadjacent 0 atom can form part of a hydroaromatic ring.

' The present invention also includes processes for the production ofesters of the above-defined glycols.

The present invention consists in a process for the production of suchtertiary-secondary glycols from the corresponding hyd'roxy-ketones ofthe general formula r R Rite t In the investigation of this reaction theunexpected observation has been made that only under strictly definedconditions, these hydroxy-ketones could be hydrogenated to the desiredglycols. Under mild conditions of temperature and pressure one or eventhe main reaction taking place is hydrogenolysis, that is replacement ofthe tertiary hydroxyl group by hydrogen, followed or accompanied by areduction of the keto-group to the secondary alcohol group. Under mildconditions, therefore, secondary alcohols of the general formula R e t(BE are formed to a considerable extent. tures of 75-125 and preferably80-90 be used and pressures between 100 and 1000 and preferably pressurebetween 500 and 1000 pounds per sq. in. are employed. Then, thehydroXy-ketones are transformed quickly and with substantiallyquantitative yield into the desired tertiary-secondary glycols.

The lower members of the series are soluble in water and are isolatedpreferably by salting out with potassium carbonate or sodium carbonate.The concentrated aqueous carbonate solution is, of course, evaporated todryness and Tempera- C. have to 2 the residue is re-used for subsequentbatches. Instead of the salting-out, other methods can be convenientlyused for the isolation of those members of the group which are misciblewith water, e. g. extraction with water-immiscible selective solvents,adsorption on specific adsorbents, or extractive or azeotropicdistillation.

The new glycols form colorless viscous liquids which are miscible orsoluble in water and equally in most organic solvents. Whilst the firstmember of the group, tri-methyl-glycol, is soluble in benzene andmixtures of benzene with petroleum hydrocarbons but not in petroleumhydrocarbons themselves, the higher representatives of the group aremiscible also with aliphatic petroleum hydrocarbons.

The substance in which R and R are both CH3 and R is isobutyl, issimilar in most of its properties to the ethyl-hexane-diol which hasrecently found industrial application.

The difference in reactivity between the tertiary and the secondaryhydroxyl groups makes selective reactions possible. Acylation, e. g.,attacks the secondary hydroxyl group more easily than the tertiary.Especially with relatively high-molecular acid chloride, mono-esters areformed; and the same is true for the Umesterung of e. g. methyl esterswith the glycols. Acetylation with acetyl chloride gives a diacetylderivative even under relatively mild conditions.

A modification of the above method permits the preparation of theisomeric mono-esters in which the tertiary hydroxyl group is acylated.This is due to the fact that it is possible to prepare the acylderivative of the above formulated hydroxy-ketone, e. g.

oco.n Pei $00.11

e. g., by acylation of the corresponding alkylbutynols.

ii tn either the same as or different from the first one.

of the triple bond. If

Dehydration of the glycols by catalytic methods in the vapour phase, e.g. in presence of activated alumina, leads successively to thecorresponding allyl alcohol by splitting ofi the tertiary hydroxylgroup, and to the corresponding. diene by split 5 ting off the secondaryhydroxyl'group too. The first (tertiary) molecule of water is split offat a temperature of 280-320" 0., while for the cat alytic formation of adiene a temperature of about 400 C. is required. The reaction is alwaysaccompanied b a pinacolonic rearrangement which leads by elimination ione molecule of water to a ketone of the general formula R1 From thetri-methyl-glycol, e. g., methyl-iso-- propyl-ketone is obtained.Separation of the isomers formed, e.-g. by passing the vapor overactivated alumina at 300,'C.,viz. methyl-isopropyl-ketone andmethyl-isopropenyl-carbinol, can be carried-outqby usua1;-methods.:---:Therearrangement to 'ketqnies also; talges yplace if .the glycols aretreated with the usual reagents bringing about suchv'pinacolonicrearrangements as -.e..g. acids. "Distillation of the glycols with smalltraces'of iodine gives againmixtures of these ketones and the isomericcup-unsaturated secondary allyl alcohols- In :view of the ease withwhich the glycols are converted into the corresponding saturated ketonesby means of acidic reagents, it is surprising thatjthe mixture, of theglycols with aldehydes, when heated in presence ofiphosphoric acid,formsi'easily and in good yields the corresponding cyclic acetals These.acetals are colorless liquids which-have high solvent power for avariety of organic substances. j

Examples of such substances are:

(11) 2.4.4.5 tetramethyl-L3 dioxolane (c)2.5-dimethyl-4-pentamethyleno-1.3-dioxolane (DEF-CH3 In these substancesthe substituents are as fol- 4 EXAMPLES [All parts are by weight]Example 1.51 parts 3-methyl-3-butanol-2- one dissolved in 200 partswater were hydrogenated at;7080 C. in presence of 5 parts of Raneynickel and with aninitial pressure of 200 lbs. The reaction took 30minutes. The reaction product was salted out from the filtered solutionby means of potassium carbonate and was distilled (1) 45/70 mm.: 7.9parts, biphasic. (2) Up to 13 mm: 6.3 parts. (3) .75-78ff/l3 rn 1jr;. 38arts.

The third fraction i the desired trimethylglycol, an odorless, colorlessviscous liquid, miscible with water, alcohol, ether, benzene, but notwith petroleum ether. Cut (1) was saturated with potassium carbonate andthe oil so obtained (1.9 parts) was combined with (2) and redistilled.3.4 parts of an oil, B. P. and 3.8 parts glycol were thus obtained. Theformer is isopropyl-methyl-carbinol, for which the-literal.

ture gives B. P. 114 Trimethyl-glycol, yield, 41.8, -parts=82%. With,500 lbs. pressure, approximately 100% yield is secured.

Example 2.51 parts 3-methyl 3-butanol-2- one in 200 parts water werehydrogenated at 70 C. and an initial pressure of 1000 lbs. Thetemperature rose to 80 C. and the absorption was completed in 20minutes. was added to saturate the water and the aqueous solutionseparated. This gave 50.5 parts trimethyl-glycol, B. P. 64/5 mm.,without any head or tail fraction. V a

If the initial hydrogen pressure had been only 200 lbs., the reactionwould be much slower and the yield of trimethyl glycol substantiallyless.

Example 52-510 parts methyl-butanolone in 500, parts water werehydrogenated starting at room temperature and an initial pressure of1100 lbs.

The amount of the Raney nickel could be 25 to 30 parts. The temperaturerose slowly to 40 C. The total reaction time was 18 hours. Potassium,carbonate treatment gave 499.5 parts trimethyl-glycol.

Example 4.71 parts 3-isobutyl-3-butanol-2- one in parts methanol werehydrogenated at room temperature and an initial pressure of 200 lbs. inpresence of Raney nickel. The reaction lasted .8hours. The solvent wasdistilled off and the residue fractionated under 13 mm. pressure.

Fraction (4) is the desired 3.5-dimethy1-hexane- 2.3.- diol, a colorlessoil miscible with water and many. organic solvents. including petroleumether. Yield, 57%; density, 0.9157; refractive index, 14455.

Analysis:

Calc. for CsH1sO2': C, 66.0; H, 12.3. Found: C, 66.3; H, 12.3.

This diol has the formula oH-om H chi 6H (5H Potassium carbonate- Thepreceding fractions (1, 2 and 3) contained 3.5-dimethyl-2-hexano1.

Example 5.72 parts isobutyl-butanolone in 80 parts isopropyl alcoholwere hydrogenated at 70 C. and 1000 lbs. initial pressure in thepresence of Raney nickel. The reaction took 2 hours and distillationgave 70 parts of the desired glycol, B. P. 84-85/7 mm.

Example 6.-72 parts isobutyl-butanolone in 80 parts isopropyl alcoholwere hydrogenated at 110 C. and 1300 lbs. initial pressure in thepresence of Raney nickel. The reaction required only 1 /2 hours. At 50mm. pressure, the 3.5 dimethylhexane-2.3-diol boiled at 125-128, and ahead fraction was obtained, which after treatment with potassiumcarbonate, gave a second crop of the glycol. Total, 69 parts.

Example 7.-50 parts trimethyl-glycol and 1 part iodine were heated in acolumn with partial take-oil. The top tempertaure was not allowed torise above 90 C. 31 parts of an oil and 6.5 parts water distilled over.The oil boiled at 94-100/760 mm.; density, 0.8132; refractive index,1.3912. It contains 27.4% carbonyl and has a bromine number of 20.2.contains 84% methyl-isopropyl-ketone and 11%isopropenyl-methyl-carbinol.

The presence of the ketone was proven by treating 6.4 parts of the oilin 40% acetic acid with 12.4 parts p-nitro-phenylhydrazine. The solidreaction product was recrystallized from methanol and formed beautifulorange-brown crystals, of M. P. 109-111, as indicated in the literature.

Example 8.If one heats 3.5-dimethy1-hexane- 2.3-diol with 0.5% iodine,the theoretically expected quantity of water distills over quickly andthe reaction product boils between 122 and 156/760 mm. 1 From thebromine number (87.5), one can conclude that it consistsof 70%3-isobutyl-3-butene-2-ol and 30% 3.5-dimethyl-2- hexano-ne.

Example 9.180 grams trimethyl-glycol were passed over 180 c. c. ofactivated alumina at 275 C. within 2 hours. The reaction product (175.5grams) was fractionated. 41 grams of the glycol were recovered, and abi-phasic head fraction of B. P. 85-130 was obtained which amounted to122 grams. After treatment of this fraction with potassium carbonate,the oil was redistilled and gave after a small head, which wasdiscarded, 58.5 grams of a water-white oil.

Analysis of this oil:

Calc. for C5H10O: C, 69.8; H, 11.7. 1 Found: C, 68.4;1-1, 11.8; C0,17.2%; bromine number 47.

As methyl-isopropyl-ketone has 32.6% C0 andmethyl-"isopro-penyl-carbinol has a bromine number of 186, one canconclude that the oil contains 52.7% of the ketone and 25.3% of theunsaturated alcohol.

The ketone was identified by means of its pnitrophenylhydrazone, asdescribed above.

7 Example 10.The homogeneous mixture of 27 grams trimethyl-glycol, 8.8grams paraldehyde and 0.4 c. c. of phosphoric acid (1.70) was boiled for10 hours. 5 o. c. of water were formed. The product was repeatedlyfractionated at atmospheric pressure and gave thus 16 grams 2.4.4.5-

'tetramethyl-dioxolan, B. P. 102-105; density,

0.8508; refractive index, 1.3975.

Analysis:

Calc. for C7H14O2: C, 64.6; H, 10.8, Found: C, 65.1; H, 11.2.

This means that it Formation of esters Example 11.Diacetyl derivative oftrimethylglycol. At 0 C., a solution of 79.2 grams acetyl chloride in100 c. c. of chloroform was added to a solution of 52 gramstrimethyl-glycol in- 80 grams pyridine. The product was treated withsulfuric acid. This settled into two layers, and the chloroform layerwas dried over calcium Calc. for the monoester 01111403: C, 57.5; H,9.6; saponification number, 384. For the diester- C9H1eO4i C, 57.5; H,8.5; saponification number, 596.

Example 12.-11.5 parts 3.5-dimethyl-hexane- 2.3-diol in parts pyridinewere added to 22.3

2 parts of the chloride of 3 cyclohexenecarboxylic acid in 37.5 partschloroform. After 24 hours at room temperature, the mass was treatedwith dilute (e. g. 10%) H2304, washed with sodium carbonate solution andthe chloroform distilled ofi". B. P. 135-137/6 mm.; yield, 14.5 parts ofthe monoester; density, 1.0138; refractive index,

Analysis:

Calc. for C15H2s0s: C, 70.9; H, 10.2. Found: C, 69.9; H, 10.0.

Example 13.10 parts 3.5-dimethyl-hexane- 2.3-diol in 50 parts pyridinewere added to a solution of 22 parts of 1methyl-3-cyclohexenoyl chloridein 37.5 parts chloroform. The treatment described in the foregoingexample gave 12.5 parts of the monoester, B. P. 125-130/6 mm.; density,1.0274; refractive index, 1.4669.

Example 14.In 34 parts trimethyl-glycol, 2 parts sodium metal weredissolved at 120 C. Then 100 parts methyl methacrylate and 5 partshydroquinone were added and the thick mass was heated for 8 hours in acolumn with partial takeoff, so that the top temperature never exceededthe boiling point of the azeotrope of methanol and methyl methacrylate,16 parts by volume distillate were obtained, containing 12.5 parts byvolume methanol which is the amount to be expected from 50% conversion(i. e. complete esterification of one hydroxyl group). The mixture Wastreated with dilute sulfuric acid and the organic product, afterdilution with ether, dried over anhydrous magnesium sulfate anddistilled. After removal (under 100 mm. pressure) of the excess ofmethyl methacrylate, the monomethacrylate of the trimethyl-glycol boiledat 76-78/6 mm.; 29.5 parts; density, 0.9945; refractive index, 1.44565.Yield, 52%.

Example 15.Tertiary mono-acetyl derivative yield, 26%.

Analysis:

Calci-for C'IH1203Z'C, 57.4; H, 8.3.

Found: C, 57.7; H, 9.0. The-aqueous layer was steam-distilled and thedistillate salted out with potassium carbonate. 21 parts of an oil Wereobtained which was methyl-butanolone. Yield, 51%. When thereaction'mixture was boiled for 1 hour (instead of keeping it atroomtemperature), no oily layer was obtained and the water gave, in themanner described, 36 partsmethyl-butanolone (yield, 87%).

(b) 33.2 parts 3-acetoxy-3-methyl-2-butanone in 160 a parts methanolwere hydrogenated at roomtemperature with Rariey nickel as catalyst. Thereaction product was distilled under 13 mm. pressure and gave 24.1 partsof the expected (tertiary) monoacetyl derivative of trimethylglycol; B.P. 62 63. Density, 1.001; refractive index, 1.4165.

Analysis:

Calc. for C'IH14O3Z C, 57.5; H, 96. Found: C, 57.4; 57.9; H, 9.1; 9.2.

Analogously one can obtain from 1- (a-hydroxyethyl) -cyclohexanol the2.5-dimethyl-4-pentamethylene-1.5-dioxolane, and from the correspondingcyclopentanone derivative the2.5-dimethyl-4-tetramethylene-l.5-dioxolane, or from 1 tetralone the 2.5dimethyl 4 benzo pentamethyleno-1.3-dioxolane Q" 011cm 011cm l CELCHa OCllHa The reaction taking place in the process of Example 10, is asfollows:

The esters produced in the processes of Examples 11, 12, 13, 14 and 15are the following:

o CH.CH3 CH3 00cm 000.0153

011-031 CH3 /('3CH.CH3

CH3 OH $00 /C OH.CHa CHsH OO.C=CHz a CH3 c-cnortoH It is to beunderstood thatthe present invention is not restricted to the treatmentof the -hy droxy-ketones mentioned aboveand in the examples. As examplesof other hydroxy-ketones suitable for treatment by the processdescribed,- I mention the following: diethyl-acetyl carbinol,

dipropyl-acetyl carbinol, ethyl-benzyl-acetyl carbinol,methyl-benzyl-acetyl carbinol, methylcyclo-pentyl-acetyl carbincl, suchlist being illustrative and in no sense limitive:

I claim:

1. A process which comprises adding a hydro genation catalyst to a3-hydroxy-2-ketone containing three hydrocarbon radicals, subjectingsuch mixture in the presence 'of water in the amount of several fold theamount of said ketone, to hydrogen under a pressure of about 500m about1000 lbs., while such mixture is at a temperature of about '70 to aboutC., and. thereafter adding an alkali metal carbonate in-such amount asto give a"substantial1y saturated solution with the water present,whereby theorganic reaction product can separate from the aqueoussolution.

2. The herein described diols having the gen eral formula in which R,and R are alkyl groups, and R and R are hydrocarbon groups, and in whicha carbon atom' of R the carbon atom adjacent thereto and a carbon atomof R may constitute three adjacent carbon atoms in a hydroaromatic ring.

ERNST BERGMANN.

REFERENCES CITED The following references are of record in the file ofthis patent:

1. A PROCESS WHICH COMPRISES ADDING A HYDROGENATION CATALYST TO A3-HYDROXY-2-KETONE CONTAINING THREE HYDROCARBON RADICALS, SUBJECTINGSUCH MIXTURE IN THE PRESENCE OF WATER IN THE AMOUNT OF SEVERAL FOLD THEAMOUNT OF SAID KETONE, TO HYDROGEN UNDER A PRESSURE OF ABOUT 500 TOABOUT 1000 LBS., WHILE SUCH MIXTURE IS AT A TEMPERATURE OF ABOUT 70 TOABOUT 125* C., AND THEREAFTER ADDING AN ALKALI METAL CARBONATE IN SUCHAMOUNT AS TO GIVE A SUBSTANTIALLY SATURATED SOLUTION WITH THE WATERPRESENT, WHEREBY THE ORGANIC REACTION PRODUCT CAN SEPARATE FROM THEAQUEOUS SOLUTION.